Black powder and method of manufacturing the same



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Patented, N... 24, 1931 UNITED STATES PATENT OFF ICE ROY LINDEN HILL, OF WILMINGTON, DELAWARE, ASSIGNOB. TO ATLAS POWDER COM- PANY, OF WILMINGTON, DELAWARE, A CORPORATION OF DELAWARE BLACK POWDER AND METHOD OF MANUFACTURING THE No Drawing.

The object of the present invention is to provide an improved explosive, of the nature many important applications; sells at a lower price than, practically, any'of the detonating explosives, but it is open to the objection that it has a low strength factor.

It has, heretofore, been proposed to increase the strength factor of black blasting powder by incorporating with the same, in the usual process of manufacture, one or more of a variety of strengthening agents, such as ammonium perchlorate, potassium perchlorate, ammonium ,nitrate, nitro-compounds and organic nitrates.

However, most of the methods, heretofore proposed, with which I am familiar, have the disadvantage of an increased hazard which renders them inapplicable to the usual black powder mills, and equipment. Some of them present the difficulty that, when incorporated inintimate contact with the usual sodium nitrate or potassium nitrate of black powder, a greatly increased hygroscopicity factor is introduced and black powder, at its best, is not of great moisture resistance. For instance, ammonium perchlorate alone is not seriously hygroscopic, but when intimately mixed with'nitrate of soda, the mixture is more hygroscopic than nitrate of soda by itself. Further, various ingredients, which might be proposed for incorporation with black powder to strengthen it, have other individual disadvantages in one or more of v such items as manufacture, handling, shipment, storage and application.

Some of the objects which should, desira-.

bly, be attained or approached in making stronger black blasting powder, are that it be adapted for manufacture in the usual black powder mills; that there be no increase in cost over usual'black powder; that normal black powder safety .in manufacture, han

dling, shipment, storage and application be maintained; that the usual methods of handlingblack p,owder,inthe respects mentioned, will apply; that there be no increase in hygroscopicity; that the product possess the capa- Application filed October 25, 1928. Serial No. 315,106.

bility of strength regulation, and that the high temperature of combustion and'the deficiency of oxygen of regular black powder be utilized toassist in increasing the strength factor.

Increased black powder. strength without any, or at least without a proportional increase in cost, represents a distinct direct savin to the consumer in powder purchases. It

such as ammonium nitrate, especially, and

various perchlorates as ammonium and potassium, as the means to secure the desired results. The oxygen carrying explosive salts used in carrying out my invention are ammonium nitrate and perchlorates, to which this application is limited. I will use ammonium nitrate in the following description of one way of arriving at the invention.

Ammonium nitrate on thermal decomposition or explosion forms gas entirely and has an explosive stren th equal to about 7.0% of that of nitroglycerine. It exerts a much greater explosive strength than sodium or potassium nitrate which are the normal oxygen carriers of black powder. 'In black powder manufacture, as is well known, sodium nitrate or potassium nitrate is incorporated under heavy wheels with sulphur and charcoal. The. product is pressed into cakes, the cakes grained and the'grains usually'separated into various sizes by screening. The grains are usually glazed with graphite, dried and packed for shipment in metal kegs.

The present invention difiers, ra dically, from 'black powder made by incorporating ammonium nitrate, sulphur and charcoal in A would 7 result, that there would be greatly increased hygroscopicity. Also, such a mixture would be less safe in the rather violent operations of wheeling, pressing and graining.

The invention oonmmpl'ates the preparation of black powder in the usual way, through the final glazing operation, as a rule, though regular unglazed powder is sometimes used and is withinthe scope of the invention. This regular black powder may be in the form of grains of quite uniform size, or in that of. grains of mixed sizes, often called run of mill in the industry. There is separately prepared the desired oxygen car rying explosive salt,as ammonium nitrate. This preparation may merely consist of drying and converting to the proper particle size, the particle size being controlled at will to suit the particular case, For the best conditions usually, the oxygen carrying explosive salt should'be in a dry,-free-flowing crystalline form. It should be coated or glazed with a material similar to that used in glazing the black powder. In many cases, it should further be given a coating of water-proofing material, such as petrolatum, paraflin or rosin. The salt may be smaller in particle size than some sizes of black powder grains and equal others. It will mix especially well with run of mill powder.

Only after both ingredients-the usual black powder and the oxygen carrying ex plosive salt-have been completely prepared, are they brought together. This simply involves good intermingling of the particles of each, which may be carried out in the usual glazing barrels, or by mixin in the manner described andthereafter pac ing in the final containers.

Thus, it will be seen that the invention answers, to a large extent, each requirement of the situation as follows:

There is ready adaptability to usual black powder mills because black powderis made as usual and crystals or particles of the oxygen carryin explosive salt may be coated and'mingle with the black powder in the usual glaze barrels and the mixture packed for shipment in the usual way.

At present prices for ammonium nitrate, the cost of the mixture would be little more than that of regular black powder. Ammonium perchlorate is somewhat more costly, but its great strength ofi'sets this to a considerable extent.

The hazard, as compared with usual black powder, in manufacture, handling, shipment,

storage and application is kept within satisfactory limits, because the oxygen carrying explosive salts are prepared separately and only mingled with the black powder as a last step. Further, the salts proposed'ammonium nitrate, ammonium perchlorate and potassium perchlorateare of a high degree of safety in handling. I distinctly eliminate chlorate from consideration. My mixtures would have lower flame lengths and temperatures, an important factor in coal mines.

My mixture would and could be handled by producer and consumer in all respects essentially as regular black powder is handled.

I avoid undue moisture absorption or hygroscopicity by refraining from mingling the salts in intimate contact, a condition usually conducive to increased absorption of moisture. Ammonium perchlorate and potassium perchlorate are of a relatively low degree ofhygroscopicity. Ammonium nitrate,

when reasonably pure, unmixed with other salts and suitably coated, is not greatly inferior to regular black powder in hygroscopicity. ll WlSh to stress the importance of my procedure of not mingling my oxygen carrymg explosive salts in intimate contact with the normal salts of black powder.

Strength regulation of the composition is simple, merely consisting in varying the proportions of black black powderand oxygen carrying explosive salts. r

Black powder has a relatively high temperature of combustion, long flame on combustion and a. large deficiency of oxygen. The flame and temperature conditions are such that excellent eificiency is derived from the presence of the oxygen carrying salts. Also the oxygen carrying salts with the oxygen deficient black powder cause a better balanced mixture forfull blastin 'efiiciency.

Since ll use my strongerblac powder over,

a widely varied range of blasting conditions, ll do not desire to limit my proportions closely. Dynamites or detonating, explosives have been made from 5% to 100% in strength. In the past, black powder has been hand-icapped by a small strength range in oomparison, which has been largely controlled by minor variations in manufactureand a variation in grain sizes. While maintaining essentially its usual characteristics, I make possible a far wider strength range and in an entirely new manner. There is no 11mitation on my mixtures, therefore, except that reliable results require not less than 40% of regular black powder present. I contemplate employing from 2 to by weight of the oxygen carrying explosive salt and from 98 to 40% by. weight of black powder.

While representing somewhat less desir able conditions, especially as regards hygroscopicit it is understood that any two or all three 0 my oxygen carrying explosive salts may be used in the same mixture, and I claim this as being within the scope of my invention.

It is emphasized that stronger black powder, in order to find extensive application, should be characterized in manufacture, shipment and application by features which keep its cost to the manufacturer and consumer,

per unit of weight, at or closely approaching that of usual b ack powder. The uality in all respects should equal or a proac h that of usual black powder. These o ects rendered necessary the adaptation of a number of conditions to the main ends. It has been explained how each adaptation has fitted into the whole and in the simplicity of accomplishment lies to an important extent the value of the invention. 1 wish to emphasize that the present invention is in therealm of low explosives and differs radically in its nature, action and field of use from detonating or high explosives and the term low explosives as used in the accompanying claims, is intended to refer to the explosives of the black powder or non-detonating 'type. I am aware of the fact that it has heretofore been proposed to use ammonium nitrate in conjunction wlth detonating explosives to increase common in the use of ordinary blasting black powder.

It is to be understood that the invention ineludes within its purview whatever changes powder and oxygen carrying "salts of ithe fairly come within either the terms or the spirit of the appended claims.

Having described my invention, what I- claim is:

1. A. low explosive of the character described consisting of intermingled grains of black powder, and an oxygen carrying explosive salt of the group consisting of ammonium nitrate and perchlorate, the grains of at least one of the said substances being coated with a protecting material.

2. The herein described method of preparing a low explosive of the nature of black powder but of stronger blasting efiiciency which consists of separately graining black powder and oxygen carrying salts of the group consisting of ammonium nitrate and perchlorate and'wherein the normal salt of the black powder is not exposed at the face of the grains of said powder, and subsequentlyintermixing these separate grains of black powder and oxygen carrying explosive salts.

The herein described method of preparing a low explosive of the nature of black powder but of stronger blasting efiiciency which consists of separately graining black group consisting of ammonium nitrate and perchlorate and wherein the normal salt of the black powderis not exposed at the face of the grains of said powder, and sub uently intermixing these separate grains of lack powder and oxygen carrying explosive salts 1n such proportions that there will be 40% to 98% by weight of black powder grains in the resultant mixture. V l

4. The processes described in claim 3, in which the grains of oxygen carryingexplosive salt are coated with a material which will cause them to have the color of black powder,

and also further separatethem from intimatecontact with the alkali metal nitrate of. the black owder.

5. T e process as described in claim 3, in

which the grains ofoxygen carrying explosive salt are coated with a moisture and waterproofing material, before intermingling with the black powder, this coating material also serving to prevent intimate contact of the grains with the alkali metalnitrate of the black powder 6. The process of prepaiing a low explosive of the nature of black powder, which avoids the hygroscopicity 'resultantfrom intimate contact of black powder with an oxygen carrying explosive salt, which consists of graining black powder, graining an oxygen carrying explosive salt of the group consisting of ammonium nitrate and perchlorate, and coating the grain of both of said materials with a material which tends to maintain separation between them. a

7..The process of preparing a low explo sive of the nature of black powder, which avoids the hygroscopicity resultant from intimate contact of black powder with an oxygen carrying explosive salt, which consists of graining black powder, graining an'oxygen carrying explosive salt of the group consisting of ammonium nitrate and perchlorate, coating the grains of each of said materials with a -material'which will tend to maintain separation between them, and there after coating the grains of the oxygen carrying explosive salt with a water-proofing composition.

8. The herein described method of preparing a low explosive blasting medium of the 2 nature of black powder which avoids the hygroscopicity resulting from intimate contact of the normal salt of black powder with oxygen carrying explosive salts of the character described, which consists of incor I crating the normal salt of black powder with combustible and coating materials which form a proteetivecoating with respect to said normal salt-of black powder, graining the incorporated mass and thereafter intermingling these grains with separate grams of an oxygen carrying explosive of the group consisting of ammonium nitrate and perchlorate.

4- a I nsaawa 9. The herein described method of pre aring a blasting medium of the nature of b ack powder, but of stronger blasting eficiency,

, which consists in separately preparing grains 5 of black powder and grains of an oxygen carrying explosive salt of the group consisting of ammonium nitrate and perchlorate, coating the grains of each of the twomaterials with a graphite, and thereafter inter- 0 mingling the grains of the two materials.

10. The process of preparing a blasting 'medium of the low explosive type, whic avoids the hygroscopicity resultant from intimate contact of black powder with am- 5 monium nitrate, which consists of graining black powder, separately graining ammonium nitrate, coating the grains of one of said materials with a substance tending to maintain separation between them, and thereafter 0 intermixing said granules.

11. The process of preparing a blasting mediurr of the low explosive type, which avoids the hygroscopicity resultant from in timate contact of black powder with an oxygen carrying) explosive salt, which consists of graining lack powder, separately graining ammonium nitrate,,coating the grains of ammonium nitrate with graphite and thereafter intermixing the separate grains of 0 powder and ammonium nitrate.

12. The process of preparing a blasting medium of the low explosive type, which avoids the hygrosco'picity resultant from intimate contact of black powder with an oxygen carrying) ex losive salt, which consists of graining lac powder, separately" graining ammonium nitrate, coating the grains'of ammonium nitrate with graphite, further coating said grains of ammonium nitrate 9 with waterproofing material, and thereafter intermixing the separate grains of powderand ammonium nitrate. a

13. A low explosive of the nature of black powder, which consists of intermixed grains of black powder andammonium nitrate, the grains of the two substances being distinctly separate from each other, and the grains of oneof said substances being coated with a material tending to maintain separation be-- tween the grains of the two materials.

In testimony whereof I afiix my signature.

' ROY LINDEN HILL.-

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